You can modify the keybindings in the menu - for example, I changed my ping back to ALT + Left-Click.

Patch 1.5 also modified the behavior so that you could ping your minimap by ping-clicking on the actual playfield you're looking at. Thus you no longer have to mouse down to the minimap, find your current view location, and then ping - you can simply ping-click the main playfield in front of you and the ping appears on their minimap at the correct location.

In patch 1.5 Blizzard changed the default keyboard mapping such that holding alt and clicking on the map or minimap no longer worked. To revert this change, load up the hotkeys dialogue and look for Quick Ping in Global - Unit Management and simply change this back to alt.